Do statins decrease testosterone in men? Systematic review and meta-analysis

ABSTRACT Purpose: Statins are one of the most prescribed classes of drugs worldwide to treat hypercholesterolemia and dyslipidemia. By lowering the level of cholesterol, the use of statin could cause a reduction in testosterone levels. The objective was to evaluate whether the continued use of statins in patients with hypercholesterolemia causes a deficiency in testosterone and other sex hormones. Materials and Methods: Systematic Review with Meta-analysis, performed in Embase, Medline and Cochrane databases, until May 2023; PROSPERO CRD42021270424protocol. Selection performed by two independent authors with subsequent conference in stages. Methodology based on PRISMA statement. There were selected comparative studies, prospective cohorts (CP), randomized clinical trials (RCT) and cross-sectional studies (CSS) with comparison of testosterone levels before and after statin administration and between groups. Bias analysis were evaluated with Cochrane Tool, The Newcastle-Ottawa Scale (NOS), and using the Assess the Quality of Cross-sectional studies (AXIS) tool. Results: There were found on MedLine, Embase and Cochrane, after selected comparative studies, 10CP and 6RCT and 6CSS for the meta-analysis. In the Forrest plot with 6CSS, a correlation between patients with continuous use of statins and a reduction in total testosterone was evidenced with a statistically significant reduction of 55.02ng/dL (95%CI=[39.40,70.64],I²=91%,p<0.00001). In the analysis with 5RCT, a reduction in the mean total testosterone in patients who started continuous statin use was evidenced, with a statistical significance of 13.12ng/dL (95%CI=[1.16,25.08],I²=0%,p=0.03). Furthermore, the analysis of all prospective studies with 15 articles showed a statistically significant reduction in the mean total testosterone of 9.11 ng/dL (95%CI=[0.16,18.06],I²=37%,p=0.04). A reduction in total testosterone has been shown in most studies and in its accumulated analysis after statin use. However, this decrease was not enough to reach levels below normal. Conclusion: Statins use causes a decrease in total testosterone, not enough to cause a drop below the normal range and also determines increase in FSH levels. No differences were found in LH, Estradiol, SHBG and Free Testosterone analysis.


INTRODUCTION
Statins are one of the most prescribed medications worldwide for lowering cholesterol.Therefore, they are efficient for the primary and secondary prevention of cardiovascular diseases (CVD) (1,2).Because cholesterol is one of the precursors of adrenocortical and gonadal hormones, there is a concern that 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors may impair testosterone production and other sex hormones (3,4).This could lead eventually to hypogonadism in men.Defined as low levels of total serum testosterone (less than 300 ng / dL) and free testosterone (less than 5 ng / dL) in combination with clinical symptoms such as low sex drive, fracture associated with osteoporosis and erectile dysfunction, or two or more of the following symptoms: sleep disturbances, depressed mood, lethargy, or decreased physical performance (5).The male hypogonadism can thus affect the function of multiple organs and the quality of life of patients.
Conflicting evidence on the subject appears in studies in the medical literature.The study by Bernini GP 1998 evaluated in 8 patients using statins for 24 weeks that there was no change in the testosterone level nor the spermogram (6).The Braamskamp MJ et al. 2015 study evaluated children with familial hypercholesterolemia for 10 years using any statin and compared them with siblings who were not using the medication and found no difference in hormone levels (7).However, in the study by Baspınar O et al. 2016, a correlation was seen between the fall in low-density lipoprotein cholesterol levels in patients using statin with the fall in the levels of total and free testosterone, in addition to exposing an association with the impairment of erectile function assessed by the IIEF-5 questionnaire.Thus, lower cholesterol levels were directly associated with lower testosterone levels and lower IIEF-5 scores (8).Other studies have shown indirect signs of significant hormonal changes, with a drop in PSA in patients without prostate cancer and an increased risk of gynecomastia in men using statins (9,10).In the cross-sectional study by Stanworth RC et al. 2009, it was not correlated the decrease in testosterone with signs and symptoms of hypogonadism, assessed by ADAM questionnaire, even though it showed a statistically significant reduction in total testosterone and SHBG (11).
Due to the contradictory findings in the literature, the hypothesis of this study is that continuous use of statins may lead to decreased levels of testosterone and other sex hormones in patients with hypercholesterolemia, potentially resulting in hypogonadism.The primary objective is to assess whether continued use of statins in patients with hypercholesterolemia causes a decrease in testosterone levels.The secondary aim is to evaluate the hormonal axis, including free testosterone, estradiol, LH, FSH, and SHBG, with the chronic use of statins.

Registration and protocol:
PROSPERO CRD42021270424 protocol registration

Eligibility criteria
Methodology based on the PRISMA 2020 statement (12).Inclusion criteria: Male patients with hypercholesterolemia or dyslipidemia or with cardiac indication for statin use.Intervention: continuous use of any type of statin such as atorvastatin, fluvastatin, lovastatin, rosuvastatin, pravastatin and others.In its various dosages as long as above the established minimum.Comparison: before and after statin use, comparison between control or placebo groups.Outcomes: Hormonal evaluation with total testosterone, free testosterone, FSH, LH, Estradiol, SHBG.Use of a questionnaire to assess sexual function.Study design: Prospective and retrospective comparative studies.Among them are randomized clinical trial (RCT), prospective cohort (PC), cross-sectional study or ecological study (CSS).Search Period: All articles published up to the date of the last search.Language: there was no language restriction.Exclusion Criteria: Patients under 18 years old.Studies that showed divergence between results and measurement units.Articles with incompletely displayed results or not submitted to peer-review journals.

Information sources
The search was carried out in MEDLINE through PubMed, Embase and Cochrane Central.The review was carried out in all databases in May 2023.Gray searches were carried out by the authors in the references of the selected articles.

Search strategy
Search strategy performed by author FPAG and revised by LSL.Strategy performed based on PICO acronym (patient, intervention, comparison, and outcome) and study objective using MESH terms.Conducted preliminary search with selection of articles to improve the search with terms found.After performing a definitive search.If during the search any article was found in the gray search that was not included in the search, the search strategy was updated.
Pubmed search strategy: (

Selection process
The article selection process was carried out in stages in order to screen the articles by double selection.Selection performed from outside paired by two authors in the stages of selection by title, abstract and full text.No automation method was used in the process.Selections were based on eligibility criteria.When an article disagreed, a third author decided.

Data collection process
Data extraction was also performed by two different authors separately, RSS and FPAG.After extraction, the data were compared with each other, and the PICO table and the results table were created in an excel spreadsheet.Any misunderstanding, a third author resolved, LSL.There was no automation of the process.
Articles that had more than one comparison group were selected, the groups that fit the selection criteria, even if there were more than two selectable groups.

Data items
The information collected was: Authors, Study year, Study country, Number of patients, Follow-up, Study design, Drug used, Drug dose, Dropouts, Total Testosterone, Free Testosterone, FSH, LH, Estradiol, SHBG, Prolactin and Erectile Dysfunction.Erectile dysfunction and hypogonadism were assessed using validated questionnaires such as the International Index of Erectile Function short form (IIEF-5) (13) and Androgen Deficiency in Aging Male (ADAM) questionnaire (14), respectively.
In case there was any information exposed in an incomplete way, it was tried to contact the authors of the articles through e-mail.If there was no response, the data was reported as not provided.

Study risk of bias assessment
To assess the risk assessment of each study, a different questionnaire was used depending on each study design.For the Randomized Clinical Trials, the Cochrane Collaboration's Tool (15) was used, for the Prospective Cohorts the Newcastle-Ottawa Scale (NOS) (16) and for the Cross-sectional Studies the AXIS tool (Assess the Quality of Cross-sectional studies) (17).Questionnaires were applied independently by two authors in each article, RSS and FPAG.

Effect measures
Data were extracted in their means and standard deviations.When the data was exposed only in confidence intervals, a conversion of the same type of standard deviation was performed.The measurement units were converted for standardization and possible comparison of variables.Total testosterone and free testosterone were evaluated in ng/dL; FSH and LH in UI/L; Estradiol in pg/mL and SHGB in nmol / L.

Synthesis methods/ Reporting bias assessment
Review Manager® software, version 5.4 (The Nordic Cochrane Center, The Cochrane Collaboration, Copenhagen, Denmark, 2020).A meta-analysis of continuous variables was used in the reverse variation test, the mean difference (MD) with a 95% confidence interval (CI) was calculated.The results were generated in graphs (18).
To assess heterogeneity, both the graphic of the forest plot and I² were analyzed.When this value was less than 50%, heterogeneity was considered low and acceptable, and the fixed model was used for analysis.When I² was greater than 50%, heterogeneity was considered important.Studies that caused heterogeneity were removed so that further metaanalyses could be conducted to assess the results, a sensitivity test.If there is true heterogeneity, the analysis model will be changed from fixed to random.
An additional analysis was performed, with the MetaDisc software (19), on the results of total and free testosterone in the statistically significant evaluations, to expose the results of the averages of the meta-analyzed groups and not just the difference between the groups.Only the values are exposed and not the graphics.
The presentation of the results was divided according to the different study designs.No other sub-analyses were performed.

Certainty of evidence
The GRADEpro tool was used to expose the degree of certainty of the evidence of the meta-analyzed and evaluated outcomes (20).

Risk of bias in studies
The risk of bias analysis was assessed using the The Newcastle-Ottawa Scale (NOS), AXIS tool and the Cochrane tool.The risks are shown in supplementary file-1 in appendix.
In the analysis with 5 RCTs, there was a reduction in the mean total testosterone in patients who started continuous use of statins, with a statistical significance of 13.12ng/dL (95% CI = [1.16, 25.08], I² = 0%,        In the Forrest plot in the analysis with 3 PC, an increase in the mean total testosterone was evidenced, without significant significance, in patients on continuous use of statins and compared with patients in the control group of -3.04 ng/dL (95% CI = [ -60.72, 54.65], I² = 92%, p = 0.92), shown in Figure -4.
In the Forrest plot in the analysis with 2 PC, an increase in the mean of free testosterone in patients who started continuous statin use of -0.17

Estradiol
In the Forrest plot with 2 CSS, a correlation between patients with continuous use of statins and In the Forrest plot with 3 PC, an increase in the mean estradiol in patients who started continuous statin use of -3.14 pg/mL was evidenced (95% CI = [-6.82,0.54], I² = 49%, p = 0.09), without statistical significance.Furthermore, the analysis of all prospective comparative studies with 4 articles showed a statistically non-significant increase in the mean estradiol of -0.

Certainty of evidence
The summary of evidence and findings are displayed in the GRADE20 table in the supplementary file 2 in appendix.

DISCUSSION
This study is a comprehensive systematic review and meta-analysis on the subject, which assesses the role of statins use on male hormones, both   in the individual and populational context.Thus, in order not to commit any ecological fallacy, it was only accepted as significant evidence, the analyzes that, when there were population studies, had their statistical result in agreement with the prospective studies.In addition, the review included all medications in the statin class used in the articles, without selecting one drug over the others, as previous reviews on the subject did, thus allowing for the effect of the class as a whole.Twenty-one articles were included with a total of 9,879 patients evaluated.
Total Testosterone was seen to decrease its mean at all levels of evidence, with the exception of the comparison between groups in the prospective studies.However, this analysis was hampered due to the low number of articles and patients evaluated, shown in the GRADE evidence summary.Therefore, it is possible to affirm that the statin use causes a decrease in the total levels of testosterone.However, these levels on average did not reach below normality, with the exception of Kannat et al. 2009 data, which were already below normality before starting the medication (46).
There was a decrease in Free Testosterone in the cross-sectional study, but no statistical difference was seen in prospective studies, as there was an important decrease in the number of studies that analyzed the variable.Therefore, it is not possible to state that statin causes a decrease in free testosterone.
Analysis of FSH showed a statistically significant increase in the hormone after statin use.As for the analysis of LH, Estradiol and SHBG, it was not possible to identify statistically significant differences (57).
The limitations of the study were the quality of the data, the mode of exposure of the variables, the variability of the medication, the exposure time and the lack of clinical evaluations.For example, patients with metabolic syndrome and obesity are at risk of testosterone deficiency and usually take statins, and those situations were not evaluated in the studies.
Data quality was a limiting factor, as some articles presented the hormonal outcome as a secondary outcome.In addition, the large variability of data measurement units was one of the possible biases, as it was the cause of the inconsistency of the data in the articles, being a reason for the exclusion of some articles.To homogenize the data, it was necessary to convert units, which generate a limitation and a potential error.For this, the conversion was performed and verified repeatedly by more than one author.
The analysis of several drugs grouped, in different doses and different exposure times can be a potential limiting factor of the evidence, but all the articles included used validated drugs, in their therapeutic dose and with a minimum period of 3 months.Furthermore, the study was unable to establish a correlation between the extent of reduction in total cholesterol levels and the decrease in total testosterone levels.Only a few groups of articles were selected, since not all groups fit the eligibility criteria.
It was not possible to assess sexual function and signs and symptoms of hypogonadism as studies did not assess these data.
Limitations of the human selection process, which include potential selection or analysis errors, were mitigated by employing the methodology recommended by PRISMA, as outlined in the methodology section (12).
Regarding practice implications, the results indicate that statin administration is associated with a decrease in testosterone levels.While this decrease is statistically significant, its clinical relevance may not be substantial.However, in patients at high risk or exhibiting symptoms of hypogonadism or ADAM, statins may contribute to clinical symptoms.Concerning future research directions, there is a necessity for further investigation into the potential relationship between statin use and clinical outcomes such as hypogonadism, ADAM, and erectile dysfunction.To elucidate more accurately the impact of statin or cholesterol reduction on testosterone levels and its clinical consequences, welldesigned, multicentric randomized clinical trials are essential.These trials should include control groups of patients using benzofibrates and/or engaging in behavioral modifications like dietary changes and increased physical activity.

CONCLUSION
Statins use causes a decrease in total testosterone, not enough to cause a drop below the normal range and also determines increase in FSH levels.No differences were found in LH, Estradiol, SHBG and Free Testosterone analysis (n = 990) Reports sought for retrieval (n = 42) Reports not retrieved (n = 0) Reports assessed for eligibility (n = 42) Reports excluded: (n= 21) -Oncology patients (n= 1)

Figure 3 - 3
Figure 3 -Total testosterone -Before and After -All Prospective Comparative Studies: Prospective Cohort and Randomized Clinical Trial.

Figure 7 -
Figure 7 -FSH -Before and After -All Prospective Comparative Studies: Prospective Cohort and Randomized Clinical Trial.

Figure 9 -
Figure 9 -LH -Before and After -All Prospective Comparative Studies: Prospective Cohort and Randomized Clinical Trial.

Figure 11 -
Figure 11 -Estradiol -Before and After -All Prospective Comparative Studies: Prospective Cohort and Randomized Clinical Trial.
Does a statin c ause a dec rease in Testosterone and other hormones in male patients with hyperc holesterolenism?Setting: Patients with Hyperc holesterolemia Bibliography: